Physico-Chemical, Microbiological and Sensory Characteristics of Yogurt as Affected by Added Lactose

Abstract

Enrichment of yogurt with lactose addition may increase the growth of the yogurt starter culture (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) and enhance yogurt physico-chemical and sensory attributes. The objectives of this study were to determine the influence of added lactose on the 1) physico-chemical characteristics, including the final lactose content of yogurt, during its shelf life; 2) growth of the yogurt starter culture over yogurt shelf life and 3) the sensory attributes of yogurt. Fat free plain set-type yogurt was manufactured using 0%, 1%, 3% and 5% w/w added lactose to accomplish objectives 1 and 2. For objective 3, a blueberry yogurt was manufactured using the same lactose levels. Analyses for plain set-type yogurt were conducted at 7 days intervals during 35 days of storage. Sensory evaluation was conducted on flavored yogurt three days after its manufacture. Data were analyzed using Proc Mixed model of SAS® 9.3 program. Significant differences between means were analyzed at α = 0.05 using Tukey adjustment. Lactose addition influenced some of the yogurt characteristics in a positive manner. Lactose contents of yogurts with lactose added at 1%, 3% and 5% stayed higher in that proportion than control throughout the 35 days of storage. Yogurts containing 5% w/w added lactose had the lowest pH. Yogurts containing 5% w/w added lactose had significantly the highest syneresis values compared to 0%, 1% and 3% w/w added lactose during storage period at day

Evaluación de la aceptación de yogurt de fresa, aplicando mapeo de preferencias

“…Un yogur con una alta aceptación por parte del consumidor debe tener, en general, una textura suave, uniforme (Jørgensen & Abrahamsen, 2019) estar libre de grumos, granulosidad y separación visual del suero; y debe tener un sabor a yogur limpio y típico. (Mena & Aryana, 2019). Las principales características de calidad sensorial del yogur incluyen textura, sabor y aroma.…”